This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | -1 |
| 3 | -8 |
| 4 | 9 |
| 5 | 201 |
| 6 | -89 |
| 7 | -8721 |
| 8 | -5599 |
| 9 | 540595 |
| 10 | 1091551 |
| 11 | -43580206 |
| 12 | -159753527 |
| 13 | 4318835223 |
| 14 | 24185472039 |
| 15 | -506659112324 |
| 16 | -3987724324735 |
| 17 | 68460979242171 |
| 18 | 722884820238847 |
| 19 | -10431188525128096 |
| 20 | -143862807220127799 |
| 21 | 1761112732849258195 |
| 22 | 31284729872945906919 |